Garner reportedly approached Shookus' ex Kevin Miller and told him 'she had proof' of the affair.

Ben Affleck and Lindsay Shookus have fuelled dating rumours with their numerous outing together in recent days. The pair has been spotted on a "very intimate" date night, a quick summer getaway to London and most recently on a coffee run.

People magazine previously claimed in its report that the two were involved in 2013, while they were married to other people. The Saturday Night Live producer was married to SNL executive Kevin Miller, while Justice League star to Jennifer Garner. Shookus ended her marriage to Miller in 2014, while Affleck and Garner are going through their divorce.

"[Affleck and Shookus] full-on had an affair. They would fly back and forth, but he would mostly visit her in New York," a source previously told the celebrity new website. "They didn't hide... They would use the Mandarin Oriental [hotel]. They were regulars."

"Both of them were married at the time. They were having secret rendezvous every time he came into New York City and other places too," another source said. "Both of them were cheating on their spouses so they were very careful about it. Jen and [Shookus'] husband both found out about it around the same time."

Now, a report from the celebrity news websites claims that Garner confronted the Saturday Night Live producer in person once she found out about her affair with The Accountant star in 2015.

Garner was apparently "on a work trip to New York City" when she approached Shookus "about the fling." However, according to the report, Lindsay refused to end the affair.

"Lindsay refused to back down or quit the affair," a source said. To this day, the two women "do not have any relationship," another source added.

Garner reportedly approached Shookus' ex Miller and told him "she had proof" of the affair and apparently showed him text messages between the rumoured couple.

That being said, other sources have said that the two didn't date before their respective separations. "The friendship's been going on for a very long time but this is newer waters for them. They've been trying to take it slow but it's progressing quickly. Their feelings are strong."